Whats the difference between a BOV and Dump Valve

Many people "talk the talk" around the car clubs and meets. I often listen to the discussions from the side lines and chuckle about some of the misconceptions. A few petrol heads have asked me to set the record straight about a "dump" valve and the BOV (blow off valve) - this is the video that covers the topic. Enjoy.

[@ericn7698]

Any day I learn something new is a good day, especially if that knowledge is in the realm of automotive performance. Great video, Chris. Thanks!

[@TurboDirectSA]

Pleasure sir - more to come next week.

[@jesus_built_my_hotrod]

I learn something with every single one of your videos

[@TurboDirectSA]

Thanks for sharing -im glad you enjoying.

[@road_2_pow_r]

well when the garrett came out the box i was like wtf... nice video. today i learned something

[@TurboDirectSA]

Im glad you enjoyed - more to come soon.

[@user-pw6ov6rq5l]

Straight on point and very clear

[@TurboDirectSA]

Thank you

[@IngeBall]

Excellent!

[@dazzmatazz]

All I need to know is which one makes the coolest sound :-)

[@JackFN_VR64]

Nice man. Say, do have a video about turbo flutter and BOV's? Why for example do rally cars chirp while road cars stu-stu-stu?

[@TurboDirectSA]

Thanks for the compliment. We dont have a video on this as yet, its a simple explanation depending from car setup to the next. I involves boost control, hardware choice and anti-lag during the running of the engine and how gear changes are programmed in the ECU etc.

[@NelsonSakwa]

The EFR has an inbuilt recirculation valve and I am just trying to understand, when does it make sense (i.e. boost pressures) to switch it to a BOV or Dual Port (part diverter, part blow off) ? I am talking specifically of the 6758 EFR on a 2L vw engine. Some guidance will really help, thanks. I know switching is possbile via block offs, relocation kits, turbosmart shortie valves etc.

[@TurboDirectSA]

Totally up to you and your preference really - if you want to hear the dump, switch to a BOV, if your ECU wants to see the recirc - then use Dual discharge designs, and if you want it silent, then use a DV --

[@NelsonSakwa]

@@TurboDirectSA Thanks very much for the reply. My question also stemmed from the fact that in our market most people running big turbos solely use BOV instead of recirculation and was wondering in general why they don't use DV. Is it that most don't work well with big turbos?

[@TurboDirectSA]

@@NelsonSakwa All i can assume is that the usual "bigger is better" is the possible reason. Back to back tests can show the results -
I have conducted tests on an RB26DETT in my own R33 Skyline GTR where we removed two HKS2540 turbos and replaced them with smaller GT2860RS turbochargers and made more power at 1000RPM sooner engine RPM - bigger is not always better.

[@jeromelevesque8330]

What's the difference between Garrett dump valve and a internal wastegate ?

[@TurboDirectSA]

The internal wastegate control and manages boost throughout the engines operation. The Dump vlave is a protective valve that only works once, and when the fuel governor fails or there is an engine runaway that results in an overboost - once the valve has dumped, it remains open (some designs are different) and will essentially prevent any boost from being generated at all.

[@redda991]

Do you think it could be done a twin scroll turbo on a 4.2L landcruiser 1HDT FTE ?

[@TurboDirectSA]

A dump valve? Sure why not - but for what reason? The 1HD FTE is fuelled electronically - so no real reason to have a dump valve.

[@redda991]

@@TurboDirectSA I mean putting a twin scoll turbo on a Landcruiser with a custom exhaust manifold.

[@TurboDirectSA]

@@redda991 Sure why not - build a separated manifold and off you go.

[@jandregerber9696]

Hi Jason. Did you explore using a twin scroll turbo on a 1HDFTE?

[@RhadenTV]

Good video, but your explanation on why cars with a MAF sensor need recirculation is a bit wonky xD

[@TurboDirectSA]

Whats Wonky about it?

[@gazza8596]

It won't let me like your video haha